grading isn't about understanding the concepts. The point here is to learn the concepts, not check off boxes.
Too many kids get way too good of grades by playing the game and checking off boxes. Too many kids, on the other hand, understand the concept but aren't willing to check off boxes so they get bad grades.
But checking off boxes isn't about learning the subjects concepts, its about following the rules. Some argue that isn't an education, its a boot camp.
I, generally, agree with them.